Skip floor structure

ABSTRACT

This invention is to transmit the horizontal force between the general floor portion and skip floor efficiently, to avoid the damage to the boundary part between the skip floor structure and the general floor portion in the event of an earthquake or the like, and can heighten the degree of freedom in design by reducing restrictions on the building form.As a solution, skip floor structure of this invention has the bellyband beams (5) constructed at the same height level as the floor beams (1) above or below the outer peripheral floor beams (3) of skip floor (4).In addition, transmission beams (10) for transmitting horizontal force from the outer peripheral floor beams (3) to the bellyband beams (5) are interposed at key points between the outer peripheral floor beams (3) and the bellyband beams (5).

TECHNICAL FIELD

The present invention relates to a structure of a skip floor to be provided mainly in a wooden house in a state where a step is formed with respect to a general floor portion.

BACKGROUND ART

In a case where a skip floor with which a step is formed between the skip floor and the general floor portion is provided in a house, there is a problem when an earthquake or the like occurs that horizontal force is not efficiently transmitted between the general floor portion side and the skip floor side, separate movement occurs, and damage is likely to occur especially at a boundary part between the general floor portion and the skip floor, that is, at the step part.

Accordingly, various structural reinforcement measures are required in order to solve such a problem. However, at present, there is no official design standard regarding a skip floor, and only a few guidelines can be used as a reference.

With reference to those guidelines, in a case where a skip floor is provided, it has been proposed that structural plywoods (35) (35) are attached across an outer wall surface (32) on the general floor portion (31) side and an outer wall surface (34) on the skip floor (33) side as shown in FIG. 5, and the outer wall surfaces (32) (34) are integrated, so that the general floor portion (31) side and the skip floor (33) side are interlocked.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No. H09-041480

SUMMARY OF THE INVENTION Technical Problems

However, in the structure in which the structural plywoods (35) (35) are attached as described above, the outer wall surface (32) on the general floor portion (31) side and the outer wall surface (34) on the skip floor (33) side are required to be disposed in the same plane. Moreover, because of existence of the structural plywoods (35) (35), there are many restrictions on the building form such that openings (36) (36) cannot be provided near the boundary part of the outer wall surfaces (32) (34), and the degree of freedom in design is lowered.

Therefore, an object of the present invention is to solve the above problems by providing a skip floor structure that efficiently transmits horizontal force to and from the general floor portion side, can suppress damage to the boundary part between the skip floor structure and the general floor portion in the event of an earthquake or the like, and can heighten the degree of freedom in design by reducing restrictions on the building form.

To solve the above problems, this skip floor structure is comprised of a bellyband beam constructed above or below an outer peripheral floor beam of a skip floor at the same height level as a floor beam of a general floor portion and transmission beams for transmitting horizontal force from the outer peripheral floor beam to the bellyband beam interposed at key pints between the bellyband beam and the outer peripheral floor beam. Concretely, at least one of the transmission beams is disposed on each side of the skip floor and the transmission beams are disposed directly below a bearing wall provided on the bellyband beam.

Moreover, the transmission beams are joined to the outer peripheral floor beam and the bellyband beam using a tenon.

Also, the bellyband beam is constructed above the outer peripheral beam, a pair of opening columns are erected on the outer peripheral beam at a lacking portion where a part of the bellyband beam is lacking, and the bellyband beam divided by a lack is coupled to the opening columns, so that an opening such as a window or an entrance door is provided between the opening columns.

DESCRIPTION OF FIGURES

FIG. 1 Perspective figure for frame structure of a wooden house, which employed skip floor structure, showing one embodiment of this invention

FIG. 2 Longitudinal section figure showing the joined state of peripheral floor beam, transmission beam and bellyband beams

FIG. 3 Front figure near the opening

FIG. 4 Figure showing a wooden house with few restrictions on the building

FIG. 5 Figure showing a wooden house with many restrictions on the building

DESCRIPTION OF EMBODIMENT

The following description will explain an embodiment of the present invention in detail with reference to the drawings. FIG. 1 shows a frame structure of a wooden house in which a skip floor structure according to an embodiment of the present invention is employed. In the figure, denoted at (1) (1) . . . are floor beams of a general floor portion (2) on the second floor of a house, and denoted at (3) (3) . . . are outer peripheral floor beams of a square skip floor (4) located lower than the general floor portion (2).

In addition, in a boundary part (6) between the general floor portion (2) and the skip floor (4), the floor beam (1) and the outer peripheral floor beam (3) are overlapped at an interval in the vertical direction.

Directly above the outer peripheral floor beams (3) (3) . . . excluding the boundary part (6), bellyband beams (5) (5) . . . are constructed at the same height level as the floor beams (1) (1) . . . of the general floor portion (2) along those outer peripheral floor beams (3) (3) . . . . These bellyband beams (5) (5) . . . are coupled in a U-shape, and the floor beam (1) of the general floor portion (2) is located in the open part of the U-shape.

That is, the bellyband beams (5) (5) . . . and the floor beam (1) are coupled in a square shape and disposed directly above the outer peripheral beams (3) (3) . . . coupled in a square shape.

In addition, transmission beams (10) (10) . . . for transmitting horizontal force from the outer peripheral floor beams (3) (3) . . . to the bellyband beams (5) (5) . . . are interposed at key points between the outer peripheral floor beams (3) (3) . . . and the bellyband beams (5) (5) . . . .

These transmission beams (10) (10) . . . are each made of a wooden square timber as with the floor beams (1) (1) . . . , the outer peripheral floor beams (3) (3) . . . , and the bellyband beams (5) (5) . . . , and are joined to a bellyband beam (5) and an outer peripheral floor beam (3) by inserting the upper half of each of tenon pipes (11) (11) . . . inserted into an upper surface part of the wooden square timber into a lower surface part of the bellyband beam (5) and inserting the lower half of each of tenon pipes (11) (11) . . . inserted into a lower surface part of the wooden square timber into an upper surface part of the outer peripheral beam (3) as shown in FIG. 2.

It is to be noted that the transmission beams (10) (10) are also interposed at key points between an outer peripheral floor beam (3) and a floor beam (1) in the boundary part (6), and are joined to the floor beam (1) and the outer peripheral floor beam (3) using tenon pipes (11) (11) . . . as with the above description.

In addition, at least one of these transmission beams (10) (10) . . . is disposed on each side of the skip floor (4) while being placed between a bellyband beam (5) and an outer peripheral floor beam (3) and also between the floor beam (1) and the outer peripheral floor beam (3) without protruding laterally, so as not to interfere with wall surface construction. As a result, horizontal force applied to the outer peripheral floor beams (3) (3) . . . can be transmitted uniformly and efficiently.

Moreover, in a case where a bearing wall (16) having a brace (15) on the bellyband beam (5) is disposed, a transmission beam (10) is disposed directly below the bearing wall (16).

Furthermore, in a case where an opening (20) such as a window or an entrance door extending to the floor level is provided in the skip floor (4), a part of the bellyband beam (5) is caused to lack as shown in FIG. 3, so that a pair of opening columns (22) (22) are erected from the outer peripheral floor beam (3) in the lacking portion (21). In addition, the bellyband beams (5) (5) divided by the lack are coupled to those opening columns (22) (22), at least one of the transmission beams (10) (10) is disposed at each of both sides of the lacking portion (21) so as to compensate for the decrease in strength due to the lacking portion (21), and the opening (20) such as a window or an entrance door is provided between the opening columns (22) (22).

In a case where the opening (20) is provided in the boundary part (6), it is to be noted that the floor beam (1) is caused to lack as shown in FIG. 1, so that the opening columns (22) (22) are erected as with the above description.

Regarding the above configuration, when an earthquake or the like occurs, horizontal force applied to the outer peripheral floor beams (3) (3) . . . of the skip floor (4) is transmitted through the transmission beams (10) (10) . . . to the bellyband beams (5) (5) . . . located at the same height as the floor beams (1) (1) . . . and to the floor beam (1) of the boundary part (6), and therefore the horizontal force is efficiently transmitted between the general floor portion (2) side and the skip floor (4) side, and the general floor portion side and the skip floor side are integrally interlocked. Accordingly, excessive force is not applied to the boundary part (6) between the general floor portion (2) and the skip floor (4), and damage to the boundary part (6) can be prevented.

In a case where the skip floor (4) is provided as described above, a new reinforcement measure different from a conventional method of attaching a structural plywood to the outer wall surface is realized, and therefore the outer wall surface (25) on the general floor portion (2) side and the outer wall surface (26) on the skip floor (4) side can be disposed in a shifted state as shown in FIG. 4, and openings (27) (27) can be provided near the boundary part (6) of the outer wall surfaces (25) (26).

It is to be noted that the present invention is not limited to the above embodiment, and it is clear that many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, although the outer peripheral floor beams (3) (3) . . . of the skip floor (4) are located lower than the floor beams (1) (1) . . . of the general floor portion (2), and the bellyband beams (5) (5) . . . and the transmission beams (10) (10) . . . are disposed above the outer peripheral floor beams (3) (3) . . . in the above embodiment, the bellyband beams (5) (5) . . . may be constructed below the outer peripheral floor beams (3) (3) . . . , so that the transmission beams (10) (10) are interposed between the outer peripheral floor beams (3) (3) . . . and the bellyband beams (5) (5) . . . in a case where the outer peripheral floor beams (3) (3) . . . are located higher than the floor beams (1) (1) . . . .

Advantageous Effects of Invention

As is clear from the above description, horizontal force applied to the outer peripheral floor beams of the skip floor is transmitted through the transmission beams to the bellyband beams disposed at the same height level as the floor beams of the general floor portion, so that the skip floor and the general floor portion can be integrally interlocked in the present invention. It is therefore possible to establish a new planning guideline for a skip floor structure capable of heightening the degree of freedom in design by reducing restrictions on the building form, since, for example, damage to the boundary part between the general floor portion and the skip floor can be prevented without providing a structural plywood as described in conventional guidelines, the outer wall surface on the general floor portion side and the outer wall surface on the skip floor side can be disposed in a shifted state, and an opening can be provided near the boundary part.

Moreover, by disposing at least one transmission beam on each side of the skip floor, horizontal force applied to the outer peripheral floor beam can be transmitted uniformly and efficiently, and highly reliable seismic performance can be demonstrated.

Furthermore, by disposing the transmission beams directly below the bearing wall or disposing the transmission beams around the lacking portion of the bellyband beams generated by forming the opening, the strength can be effectively reinforced.

DESCRIPTION OF REFERENCE SIGNS

-   1 Floor beam -   2 General floor portion -   3 Outer peripheral floor beams -   4 Skip floor -   5 Bellyband beams -   10 Transmission beams -   11 Tenon pipes -   16 Bearing wall -   20 Opening -   21 Lacking portion -   22 Opening columns 

1. A skip floor structure comprising: a bellyband beam constructed above or below an outer peripheral floor beam of a skip floor at the same height level as a floor beam of a general floor portion; and transmission beams for transmitting horizontal force from the outer peripheral floor beam to the bellyband beam interposed at key points between the bellyband beam and the outer peripheral floor beam.
 2. The skip floor structure according to claim 1, wherein at least one of the transmission beams is disposed on each side of the skip floor.
 3. The skip floor structure according to claim 2, wherein the transmission beams are disposed directly below a bearing wall provided on the bellyband beam.
 4. The skip floor structure according to claim 3, wherein the transmission beams are joined to the outer peripheral floor beam and the bellyband beam using a tenon.
 5. The skip floor structure according to claim 4, wherein the bellyband beam is constructed above the outer peripheral beam, a pair of opening columns are erected on the outer peripheral beam at a lacking portion where a part of the bellyband beam is lacking, and the bellyband beam divided by a lack is coupled to the opening columns, so that an opening such as a window or an entrance door is provided between the opening columns.
 6. The skip floor structure according to claim 5, wherein at least one of the transmission beams is disposed on each of both sides of the lacking portion of the bellyband beam. 